In this section we will give you information about the different kinds of locks and latches, and how you should go about fitting them. There is also information about maintaining and repairing lock, such as changing the lock barrel. We also explain all the common terms and parts of locks and latches.

Check your mortice latches are insurance approved

First of all you need to understand if you have the right lock and if not which lock is right for you.

Have I got the right lock or which lock should I choose?

Locks are often the first and most important security element for deterring and stopping a potential thief. It is important to select the right lock in the first place, or if the locks are already there, you should assess if the current lock is suitable for your needs.

Some of the most important things to consider when assessing if you have the right lock, or are choosing the right lock are:

The lock strike plate: This is the plate of metal (usually) that is attached to the door frame or door jamb. It secures the whole lock into the door frame when it is locked and it is not simply for decoration. It is typically one of the weakest parts of the lock and where a burglar can attack the lock with a crowbar. It should be made of heavy gauge metal, firmly secured with enough long screws – ideally a minimum of 4. This is the easiest part of the lock to change but you will struggle to find them sold separately as they typically come as part of the lock set.

Extra security with a Dead bolt: A dead bolt is more secure as it needs the whole lock cylinder to turn the lock rather than a just a spring mechanism pushing the bolt. A spring bolt lock uses a spring to push the bolt into place and this can be forced back by a determined intruder so it is much less safe.

Double Cylinder protection: A double cylinder lock requires a key both on the inside and the outside to open it. This affords an extra level of protection and will act as a deterrent to a would be thief; if entry is made through a window the burglar still cannot leave easily with his stolen goods as he cannot unlock the door and burglars hate to be in a situation where their getaway is restricted.

The Bolt: The material that the bolt is made of will determine it’s strength – steel is good. The length that the bolt protrudes into the door jam is important; this is known as the ‘throw’ and a 1 inch throw is pretty typical. If you are really concerned about security there are locks available with bolts which have pins inside them that spin if the bolt is cut with a saw making it nearly impossible to cut the bolt.

Go high tech: There are now locks available that are digital and can be opened with codes, finger prints and remote controls. We’re really traditionalist here are DIY Doctor and prefer the old fashioned stuff, but it can be just the thing for some people!

The weakest link: It is no good having the most amazing lock in a flimsy door. If the door frame is not strong then it will be the thing that gives way first so consider getting a London or Birmingham bar fitted to the door jam. These are strengthening bars that support door frame.

Some Definitions and Explanations of Locks and Lock Parts:

Strike plate: A strike plate is the metal plate attached to the door post or door jamb through which the latch and bolt pass to hold to door closed. The primary purpose is to protect the jamb from the rubbing of the bolt and they improve security by strengthening the door jambs which are typically made of wood.

Door Jamb: Door Jambs are the vertical sections of the door frame which the door fits into when closed. They are important because the bolt of the lock protrudes into them when locked to secure the door. They are also referred to as the door post or doorjamb.

Dead bolt: A dead bolt describes a locking mechanism that can only be locked and unlocked by turning the lock cylinder. This is different to a spring bolt lock or night latch which uses a spring to push the bolt.

Night latch: (or Spring bolt lock) A night latch is a lock that is operated by a key on one side and a knob or leaver on the other. The classic example of this is the Yale lock which is a cylinder night latch. The version of this that is generally accepted and requested by insurance companies is the Rim automatic deadlatch with key-locking handle – Yale and other leading brands are typical examples of this type of lock.

Night latch: (or Spring bolt lock) A night latch is a lock that is operated by a key on one side and a knob or leaver on the other. The classic example of this is the Yale lock which is a cylinder night latch. The version of this that is generally accepted and requested by insurance companies is the Rim automatic deadlatch with key-locking handle – Yale and other leading brands are typical examples of this type of lock.

Lock Cylinder: This is the “brains” of the lock and where the key is matched up to see if the lock will turn. It can be re-keyed if you have lost the keys, or if it is damaged, say the key has broken off in the lock, it can be removed and replaced. You will find information about how to do this in this section – see the links above.

Latch: A Latch is simply a mechanism for fastening one object to another, if this scenario we are talking about doors or window being fastened to their frames. There are a great variety of types as you can see below.

Mortice lock: (Spelt Mortise in North America.)This is a lock that fits into a recess which is cut into the edge of the door, know as a mortice. To see how to fit one have a look at the project about fitting a mortice latch.Insurers will look for a five leaver mortice lock and a five-lever mortice deadlock conforming to BS 3621 will give a higher level of security and should be reflected in your insurance premium.

Bored cylindrical lock: These are locks that are cheap to produce and quick to fit and so are growing popularity. They differ from a mortice lock in that rather than having the body of the lock fitted into a pocket cut into the edge of the door, a hole is simply bored into the edge and another hole if bored into the face of the door crossing the first hole perpendicularly. This means it much quicker to fit.

Lock Set: This is a term that refers to all the parts of the lock, including the strike place, the lock body, lock cylinder and all the lock trim, which is all the various knobs and levers that come with the lock to open the door.

Double cylinder lock: A double cylinder lock will accept a key from both sides, inside and outside, and as a result it often doesn’t have a knob to open the door, on either side. It differs from the single cylinder lock which will only accept a key one side and will have a knob or leaver to open the door from the other side, invariably the inside.

Lock bolt: The bolt is the typically metal, rectangular part of the lock that protrudes when locked and is inserted into the door jam, through the strike plate, to secure the door in the locked position.

Throw (of a lock): The distance that the bolt is pushed by the lock mechanism into the door frame or door jamb.

Key-operated multi-point locking system: You will typically see these in patio and bifold doors and they are a locking system that is built into the stiles or edges of the door. With the key a number of locking catches and hooks will be triggered to hold the door shut.

Types of Latch Explained:

There are a variety of common latches and we will give you an explanation of how they work and where they are used:

Slam Latch: This is a latch that closed when slammed. There are a wide variety of styles and uses for this sort of mechanism.

Suffolk Latch: This is a traditional style latch which uses a thumb operated leaver to lift the latch for opening the door.

Norfolk Latch: This is very similar to and is an enhancement on the Suffolk Latch. It incorporates a back plate where the thumb piece is attached.

Bolt or cross bar: This is a very simple form of latch where the bolt is slid into an eye or hole in the door or gate frame to secure it closed.

Hasps and hooks: These are simple catches and hooks that fasten a door closed. They are easy and quick to fit and can have a padlock added to improve security.

Spring Latch: There are a number of varieties of this kind of latch. The most common is the latch bolt which is part of a lock set and is spring loaded; when the door is closed the angled bolt allows the door to close and then springs out catching it on the strike plate or catching mechanism. A night latch is a type of spring latch that is built into a lock and therefore has the ability to be locked.

This section will give you all the information that you need to fit, fix and repair lock and latches. With a clear idea of what you need and how to choose the right lock for your home, we explain all the jargon and give you definitions of the common terms you will need to complete your DIY lock project.